Apparatus for casting metals in vacuums.



No. 755,842. v PATENTBD MAR. 29, 1904. 'W. B. BURROW.

. APPARATUS FOB. CASTING lllFtT'AIsllq- VAGUUMS.

APPLICATION FILED -IULY 2, 1902.

No MODEL.

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No. 755,842. I Y Patented March 29, 1904.

v UNITED STATES PATENT OFFICE.

. WALTER B. BURROW, OF NORFOLK, VIRGINIA.

APPARATUS FOR CASTING METALS IN VACUUMS.

SPECIFICATION forming part of Letters Patent No. 755,842, dated March 29, 1904.

Application filed J'uly 2, 1902. Serial No. 114,094. (No model.)

T @ZZ whom mfby COWCWW/f I represents guide-pins around the flange B Be it known that I, WALTER B. BURRow, a of the outside drag- A for the vregistering of citizenof theUnitedStates,residingatNorfolk, the cope O upon it.

in the county of Norfolk and State of Virginia, J represents the taper upper ends of the funhave invented a new and useful Apparatus for nel-tubes C and T for the insertion of plugs, 5v5

Casting Metals in a Vacuum; and I declare the as will be hereinafter described.

following to be afull, clear, and exact descrip- K is the sand mold of the casting in the tion of the saine. flask F and inclosed by the outside cope and My invention relates to flasks or molds for drag, as in Fig. l.

1o casting metals in arareiied atmosphere formed L is a vacuum-pipe for withdrawing the air 60 within the apparatus, thereby removing the and gases from the cope C, the drag A, and air and gases from the mold and producing the mold K. sound castings free from blow-holes, cavities, M, Fig. 1*, represents plates upon which the and other defects. sand filling G and the seal H are supported in I 5 Referring to the drawings, Figure 1 is a secposition and are located between the inner 65 tional end elevation of the apparatus, taken on flask F and the outside drag A. The plates M the line 2 3 in Fig. 3.' Fig. 2 is an elevation are used when the space R is filled with water of the complete ask or box. Fig. 3 is a plan for cooling the various parts. In ordinary of the apparatus. Fig. iis an elevation of one cases rubbish, such as cinder, can be used in 2o oftheplugs orstoppers and is usedto check the place of the water up to the plates M. In 70 inrush of air into the mold,as will be hereinsmall molds the entire spaces G and R can be after described. Fig. 5 is a partial plan of filled with sand. The plates M are placed the Hare end or flange on the outside drag or around thedrag A, as shown by dotted lines box and the metallic seal; also, a section of the in Fig. 3. I

lower end or ange of the outside cope or top, N is a plug for an opening to test the vacuum 7 5 taken on the line l in Fig. l. within the apparatus.

In the drawings, in which like letters of ref- O is a ange on the cope C, extending downerence indicate similar parts in all the views. ward into the sand iilling G and against which A is the outside drag or box. the metallic seal H is placed.

B is an angular sealing-ange around the P is the runner or riser of the mold K. SO dragA,which tapers to formaiared projection Q, is the tapered lower end of the funnel or rirn. tube C', which is inserted into the opening l? Ois the outside cope, bonnet, or top, containof the mold K. ing two or more tubes or pipes through it, as R is the water or air space around the moldshown in Fig. l. The tubes or pipes O and flask F. 85 T are preferably cast with the cope C, or the S is one of the plugs for thejfunnel-tubes lower part may be cast and the upper end O and T, U being the head rof the plug, and screwed into the cope or top. V an asbestos packing ring or gasket for main- E represents vents in the mold to allow the taining a tight joint between the plug and the 40 escape of the air and gases therefrom. funnel-tubes. 9o 1 F is the ordinary flask containing the mold The operation of the apparatus is as foland is placed inside of the outer drag A and lows: The mold K in the flask F is placed in the cope C, which entirely incloses it, as shown the outside drag or box A, and the Voutside in Fig. 1. cope or bonnet O is carefully placed over the Gis asand iilling over the water or air space box A, so that the funnel-tubes C and T will 95 R between the outside drag A and the flange enter the riser and, runner of the mold, as O of the cope or bonnet O. shown at Q in Fig. 1. The cope C is guided H is a fusible metallic seal poured on top of and kept vertical by the pins I on the flange the sand filling G, forming an air-tight joint B of the drag A. The plates M are then sebetween the two parts A and C. cured in position and the sand filling G placed IOO on top of them, or the entire spaces G and R can be filled with sand, according to circumstances. The projection or flange O of the cope or bonnet C is then pushed downward upon the sand filling G and made level. The sand is then tucked firmly around the flange O and the drag A, so as to keep the cope C from settling to one side and damaging the mold. A fusible metal or alloy in a molten state is next poured upon the top of the sand filling G between the cope-flange O and the drag A, which firmly joins the two, making an absolutely air-tight seal or joint. The space R can be filled with cinder, broken brick, and the like and the sand packed upon it, or all sand may be used, as already described. The space R is adapted for the circulation of water when the seal H is in danger of being softened or melted by the heat in the case of large steel castings, though in ordinary foundry-work a sand filling will in all probability be suflicient. The mold is well vented upward into the cope C, under which the air and gases in the mold ascends to be drawn off by means of the pipe L, connected to a vacuum-pump or other means. After the seal H is applied the metal is poured into one of the funnel-tubes C or T until it rises to within two or three inches in the other, after which the plugs S are loosely inserted into the tubes and the exhaustion commenced. After the metal is allowed to rest for a few minutes the plugs are driven in tightly and the rarefaction continued until the metal shows Signs of solidifying, at which point the connection between the pipe L and the pump is broken and the apparatus allowed to stand until cold and the flask taken apart by melting the seal H or separated forcibly from each other. The metal should be well up in the funnel-tubes C and T, so that they may act as traps or reservoirs to supply any sinking of the metal in the mold.

Heretofore the methods that have been tried for vacuum-casting have been defective, as the apparatus could not be made air-tight.

The pressure of the atmosphere on the metal in the funnel-tubes C and T tend to pack the metal firmly into the mold. By venting the mold perfectly the air and gases can be withdrawn after the metal is poured.

My invention can be modified to pour the molten material into a vacuous space previously formed in the box A and C.

The arrangements experimented upon by others have not given good results, because a cheap and perfect seal between the several parts could not be obtained, besides the devices have been too expensive.

Then the funnel-tubes C and T are suiiiciently high, the head of the liquid metal and the atmospheric pressure will make a more solid casting than is possible without my apparatus.

In my invention no air can leak into the mold or flask from the outside except through the tubes C and T, and when they are full of the molten metal the apparatus is absolutely air-tight.

The seal H is both cheap and effective and easily applied and removed.

The cope or bonnet C contains two or more tubes and sometimes only one; butgenerally two are all that are required, one being in that case a riser and the other a runner, as shown at C and T in Fig. 3.

Having described my invention, what I claim is- 1. A vacuum casting apparatus, the combination of a metallic outer drag, box or case, a flange or lip projecting outward forming a flared rim at the top of the said drag, a detachable cope, bonnet or top over and entirely inclosing the mold in its flask or box, the said outer cope or top fitting into a space on a sand filling around and between the inner moldflask and the outer drag or box, and a metallic seal at the junction of the outer cope or top and the outer drag or box, of a lowermeltingpoint than the said top part or cope and the lower part or drag, as described.

2. A Vacuum casting apparatus, the combination of a flanged outer drag, box or case, a cope, bonnet or top, detachable from the main body or lower part or drag, the said outer cope and drag inclosing the mold, a metallic seal poured in while molten upon a sand filling between the outer drag or box and the outer cope or bonnet, forming a hermeticallysealed joint between the said outer cope and drag, and tubes or pipes passing through the outer cope, bonnet or top, placed vertically upward at right angles to the plane or level ofl the top of the cope or bonnet and extending downward into the inner Hask and mold, and means for adjusting the lower ends of the said tubes to fit into the runner, riser or sink heads of the inclosed mold for the guidance of the metal therein, as described.

3. A vacuum casting apparatus, the combination of a flanged projecting flared-rim drag, box or case, a detachable cope, bonnet or top, a metallic seal at the junction of the said cope and drag, and tubes upon the said cope or top, extending vertically up and down, the lower ends of the said tubes fitting into the risers and runners of the inclosed mold and the upper ends acting as funnels for pouring the molten metal into the said mold, and refractory packed metallic plugs or Stoppers, for closing and opening the funnel-tubes, and an outlet-pipe for removing the air and gases from the said rnold and the outer cope and drag, as described.

4. A Vacuum apparatus for casting metals, the combination of a flanged detachable interlocking cope and drag, a metallic seal around the junction thereof, and guide or funnel tubes for filling the mold with the molten metal, and removable plugs for closing the IOO IIO

upper ends of the Said tubes to regulate the degree of rarefaction in the apparatus, a water jacket or space around the flange of the outside drag or case and the lower partof the cope or bonnet and under the metallic seal to prevent its fusion, and a sand filling or subseal, between the said metallic seal and the water-space, substantially as described.

In testimony whereof I have signed my name to this specication in the presence of two su I0 scrlbing wltnesses.

WALTER B. BURROW. f

Witnesses:

J A. CAMPBELL, G. T. SHEPPERD. 

